Recovering sodium sulfate and sulfuric acid.



No. 873,070. PATENTED DEC. 10, 1907 A. W. NIBELIUS.

REGOVERING SODIUM SULFATE AND SULPURIG ACID.

APPLIGATION FILED JUNBlB. 1906.

an'uenfoz CavJ. wi I,

ii/witnesses insures s'rarns PATENT cries.

AXEL W. NIBELIUS, OF EACKETTSTOWN, NEW JERSEY.

EYECQDVERING SGDIUXYL SULFATE AND SULFURIC ACID.

n0. s'zaovc.

' ing Sodium Sulfate and Sulfuric Acid from Salt Cake and Nitcr Cake, ofwhich the following is a specification.

This invention relates to a process of extracting or spa-ra'ting sodiumsulfate and sulfuric acid from uiter cake and has for its object toprovide an improved process,

. whereby such extraction or separation may slightly soluble.

be easily, economically and satisfactorily carried out.

In my improved process I effect the separation of the sulfuric acid fromthe sodium sulfate present in the niter cake by dissolving the sulfuricacid in avolatile solvent or a miX- ture of volatile solvents in whichthe sodium sulfate is either wholly insoluble or only As examples ofsuch solvents may be mentioned ethyl alcohol referably in the form ofdenaturized a cohol,

methyl alcohol preferably in the form of ordinary wood alcohol, amylalcohol in the form of fusel oil, and compounds of the said alcohols, asainyl acetate and the like.

In the practical carrying out of my process in its preferred embodimentthe procedure is as follows: Ground or granulated niter cake is mixedwith the volatile solvent in acid )roof vessels or lead lined tanks andagitated. The whole mass is then, while being stirred, pumped by meansof an acid proof pump and pipe line to filter presses where the mass isseparated under the pressure of the filter presses into neutral sulfateof sodium and a solution of the sulfuric acid in the volatile solvent.This solution which contains also the salts of iron originally pres entin the cake is then evaporated at ordinary atmos heric pressure or invacuum and the volati e solvent separated and condensed. Thisdistillation is carried out in lead lined or acid proof distillingapparatus, preferably under diminished atmospheric pressure to permit ofvolatilizing the solvent at a temperature lower than its boilin point.Distillation in vacuum is preferreo as the strong sulfuric acid thenprevented from acting chemically upon the solvent.

condensed the volatile solvent is re-used in After being Specificationof Letters Patent.

Application filed June 18. 1906.

. tile solvent.

Patented Dec. 10, 1907.

Serial No. 322,313,

the process. of sodium which remains in the filter press is then washedwith a volatile solvent of the character hereinbefore mentioned until atest for the presence of iron salts shows their absence. An anhydroussodium sulfate is thus obtained which is free from iron and ready foruse in glass manufacture or for other purposes. The sulfuric acidremaining after evaporating of the solvent is of high specific. gravityand strength.

While the proportions of the volatile solvent employed and the nitercake may be varied as desired satisfactory results can'be obtained bymixing the materials together in equal proportions by weight.

.Glaubers salt is produced in the same manner as that above described inconnection with the production of anhydrous sodium sulfate except thatin producing Glaubers salt a sufficient quantity of water is added tothe ground or granulated cake to provide water of crystallization beforethe volatile solvent is added. The solvent dissolves the sulfuric acidand precipitates the Glaubers salt (Na,SO,1o1-1,0). The mixture is thenpumped to a filter press or centrifugal machine, and the Glaubers saltseparated from the solution of. sulfuric acid and the latter from itssolvent as described above. While my improved recess is not dependcrrtupon any particu'ar apparatus for its suzccessful operation, it can beadvantageously carried out in the apparatus shown diagrammatically inthe accompanying drawing forming a part of this specification.

In this drawing reference numeral 1. designates a tank in which theground or granulated niter cake can be mixed ,with the vola- The tank 1has a lining 2 of lead or other acid proof material and is provided witha stirrer 3 adaptedto be actuated by a belt passing-around the pulley 4.C011 ncctcd. with the tank at the lower portion thereof is a pipe line 5lined with acid proof material, through which the mixed salt andvolatile solvent are pumped by the pump 6 The neutral or normal sulfateto oneor more filter presscrs 7 Where the solution' of sulfuric acid inthe volatile solvent is separated from the remaining salt and collectedin a receptacle 8. A v ipe 9 leads from the bottom of the receptac e 8to a vacuum still '10 in which the solution is distilled to separate thevolatile solvent from the acid. A pipe 11 leads from the dome of thestill to a water condenser 12 designed to separate Water which may bevolatilized with the volatile solvent from the vapors of such solvent.The pipe 13 serves to carry the condensed aqueous vapor back to thestill 10. The pipe 14 connects the Water condenser with the worm 15 ofthe condenser 16 inwhich the volatile solvent is condensed under theinfluence of a cold liquid entering the condenser through the pipe 17and passing through the pipe 18.

Reference numeral 19 designates a receptacle havi g a gage glass 20 inwhich the condensed volatile solvent is collected and referby which asuitable vacuum is i'uaintained in the apparatus.

Having thus described my invention 1 claim:

separating sulfuric acid from niter cake Whioh consists in dissolvingsaid acid in a 2. The Process hereinlurt'ore (lesci'iliid ot' isolatingsulfuric acid and a sulfate of s. idiuiu from niter cake which consistsin, addin to seld cake a volatile solvent capable iii (lI:'--

l l i 1 l i l sodium sulfate is insoluble, removing the solution of theacid from the sodium sulfate and separating the solvents from the acidby distillation.

4. The process hereinbefore described of isolating sulfuric acid and. asulfate of sodium from niter cake which consis s in adding; to said cakea volatile solvent in which said acid is soluble, but in which thesodium sulfate insoluble, removing the solution of the acid from thesodium sulfate and separating the solvent from the acid by distillationunder diminished atmospheric pressure. ence numeral 2O designates avacuum pump 5. The process hcreinhcfore described of isolat mgsulliu'ii' acidiand a sulfate of sodium. in the lorm ol' (llaubers saltfrom niter es to which consists in adding to said niter calco in i adissolved state a volatile solvent capable of 1. The'process heremhetorcdescribed of dissolving ll: 1* acid but in which the sodium sulfate isinsoluble, ren'io'viug the solution of the acid from the sodiuu'isulfate and. illlt'tll'j? separating the acid and the solvent.

6. The process herein described of isolatin; sulfuric acid. and asulfate of sodium from niter ealu, which consists in dissolving saidniter cake in water, adding: to the said niiei' cake in solution inWater a volatile sol vent capshle of dissolving the said acid, but

in which the sodium sulfate is ii'isiiiuhle, re-

iuo\in the solution of the arid from the sod i sulfate, and iinallseparating the acid and solvent, l.-

in test iiaouv n l root .l ailix my signature in presence of twowitnesses.

AXEL W. Mfr-ll ll Wi tnesses:

iaotially descrihedfi

